US4306955A - Photopolymerized acrylic polymer essentially devoid of residual monomer(s) - Google Patents
Photopolymerized acrylic polymer essentially devoid of residual monomer(s) Download PDFInfo
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- US4306955A US4306955A US06/137,484 US13748480A US4306955A US 4306955 A US4306955 A US 4306955A US 13748480 A US13748480 A US 13748480A US 4306955 A US4306955 A US 4306955A
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- 239000000178 monomer Substances 0.000 title claims abstract description 60
- 229920000058 polyacrylate Polymers 0.000 title abstract description 7
- 229910052783 alkali metal Inorganic materials 0.000 claims abstract description 16
- -1 alkali metal sulfite Chemical class 0.000 claims abstract description 15
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 claims abstract description 14
- 239000007864 aqueous solution Substances 0.000 claims abstract description 14
- 239000011248 coating agent Substances 0.000 claims abstract description 12
- 238000000576 coating method Methods 0.000 claims abstract description 12
- 238000000034 method Methods 0.000 claims description 34
- 230000008569 process Effects 0.000 claims description 30
- 239000000843 powder Substances 0.000 claims description 21
- HRPVXLWXLXDGHG-UHFFFAOYSA-N Acrylamide Chemical compound NC(=O)C=C HRPVXLWXLXDGHG-UHFFFAOYSA-N 0.000 claims description 19
- GEHJYWRUCIMESM-UHFFFAOYSA-L sodium sulfite Chemical compound [Na+].[Na+].[O-]S([O-])=O GEHJYWRUCIMESM-UHFFFAOYSA-L 0.000 claims description 14
- 239000000203 mixture Substances 0.000 claims description 10
- ATRRKUHOCOJYRX-UHFFFAOYSA-N Ammonium bicarbonate Chemical compound [NH4+].OC([O-])=O ATRRKUHOCOJYRX-UHFFFAOYSA-N 0.000 claims description 8
- 239000001099 ammonium carbonate Substances 0.000 claims description 8
- 235000012501 ammonium carbonate Nutrition 0.000 claims description 8
- 235000010265 sodium sulphite Nutrition 0.000 claims description 7
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 claims description 6
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 claims description 6
- 238000001035 drying Methods 0.000 claims description 6
- 238000000227 grinding Methods 0.000 claims description 5
- SMZOUWXMTYCWNB-UHFFFAOYSA-N 2-(2-methoxy-5-methylphenyl)ethanamine Chemical compound COC1=CC=C(C)C=C1CCN SMZOUWXMTYCWNB-UHFFFAOYSA-N 0.000 claims description 4
- 150000003839 salts Chemical class 0.000 claims description 3
- 229910000029 sodium carbonate Inorganic materials 0.000 claims description 3
- NLHHRLWOUZZQLW-UHFFFAOYSA-N Acrylonitrile Chemical compound C=CC#N NLHHRLWOUZZQLW-UHFFFAOYSA-N 0.000 claims description 2
- 239000000853 adhesive Substances 0.000 claims description 2
- 230000001070 adhesive effect Effects 0.000 claims description 2
- 229910000288 alkali metal carbonate Inorganic materials 0.000 claims description 2
- 150000008041 alkali metal carbonates Chemical class 0.000 claims description 2
- 150000002148 esters Chemical class 0.000 claims description 2
- 239000010410 layer Substances 0.000 claims 7
- 239000012790 adhesive layer Substances 0.000 claims 2
- CERQOIWHTDAKMF-UHFFFAOYSA-N Methacrylic acid Chemical compound CC(=C)C(O)=O CERQOIWHTDAKMF-UHFFFAOYSA-N 0.000 claims 1
- DWAQJAXMDSEUJJ-UHFFFAOYSA-M Sodium bisulfite Chemical compound [Na+].OS([O-])=O DWAQJAXMDSEUJJ-UHFFFAOYSA-M 0.000 claims 1
- 235000010267 sodium hydrogen sulphite Nutrition 0.000 claims 1
- WBZKQQHYRPRKNJ-UHFFFAOYSA-L disulfite Chemical compound [O-]S(=O)S([O-])(=O)=O WBZKQQHYRPRKNJ-UHFFFAOYSA-L 0.000 abstract description 10
- 229920006243 acrylic copolymer Polymers 0.000 abstract description 5
- 239000000243 solution Substances 0.000 description 28
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 15
- 229920000642 polymer Polymers 0.000 description 12
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 11
- 239000001301 oxygen Substances 0.000 description 11
- 229910052760 oxygen Inorganic materials 0.000 description 11
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 11
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 9
- LSNNMFCWUKXFEE-UHFFFAOYSA-L sulfite Chemical class [O-]S([O-])=O LSNNMFCWUKXFEE-UHFFFAOYSA-L 0.000 description 9
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 8
- 239000007788 liquid Substances 0.000 description 8
- 238000006116 polymerization reaction Methods 0.000 description 8
- 238000002360 preparation method Methods 0.000 description 7
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 description 6
- 230000005855 radiation Effects 0.000 description 6
- LSNNMFCWUKXFEE-UHFFFAOYSA-N Sulfurous acid Chemical class OS(O)=O LSNNMFCWUKXFEE-UHFFFAOYSA-N 0.000 description 5
- 229920001577 copolymer Polymers 0.000 description 5
- AEQDJSLRWYMAQI-UHFFFAOYSA-N 2,3,9,10-tetramethoxy-6,8,13,13a-tetrahydro-5H-isoquinolino[2,1-b]isoquinoline Chemical compound C1CN2CC(C(=C(OC)C=C3)OC)=C3CC2C2=C1C=C(OC)C(OC)=C2 AEQDJSLRWYMAQI-UHFFFAOYSA-N 0.000 description 4
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 4
- 150000001340 alkali metals Chemical class 0.000 description 4
- 239000008394 flocculating agent Substances 0.000 description 4
- 239000004615 ingredient Substances 0.000 description 4
- 229910052757 nitrogen Inorganic materials 0.000 description 4
- 239000000176 sodium gluconate Substances 0.000 description 4
- 235000012207 sodium gluconate Nutrition 0.000 description 4
- 229940005574 sodium gluconate Drugs 0.000 description 4
- MSAHTMIQULFMRG-UHFFFAOYSA-N 1,2-diphenyl-2-propan-2-yloxyethanone Chemical compound C=1C=CC=CC=1C(OC(C)C)C(=O)C1=CC=CC=C1 MSAHTMIQULFMRG-UHFFFAOYSA-N 0.000 description 3
- 230000009471 action Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000001125 extrusion Methods 0.000 description 3
- 239000011521 glass Substances 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 239000007858 starting material Substances 0.000 description 3
- LSNNMFCWUKXFEE-UHFFFAOYSA-M Bisulfite Chemical compound OS([O-])=O LSNNMFCWUKXFEE-UHFFFAOYSA-M 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 2
- JXSVGTPMFNKSIC-UHFFFAOYSA-L [Cl-].CC[N+](C)(C)C.CC[N+](C)(C)C.CC(=C)C([O-])=O Chemical compound [Cl-].CC[N+](C)(C)C.CC[N+](C)(C)C.CC(=C)C([O-])=O JXSVGTPMFNKSIC-UHFFFAOYSA-L 0.000 description 2
- 229920006322 acrylamide copolymer Polymers 0.000 description 2
- 229910021529 ammonia Inorganic materials 0.000 description 2
- ISAOCJYIOMOJEB-UHFFFAOYSA-N benzoin Chemical compound C=1C=CC=CC=1C(O)C(=O)C1=CC=CC=C1 ISAOCJYIOMOJEB-UHFFFAOYSA-N 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 229920002401 polyacrylamide Polymers 0.000 description 2
- 229910001220 stainless steel Inorganic materials 0.000 description 2
- 239000010935 stainless steel Substances 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- 231100000419 toxicity Toxicity 0.000 description 2
- 230000001988 toxicity Effects 0.000 description 2
- 229920003169 water-soluble polymer Polymers 0.000 description 2
- ZAFNJMIOTHYJRJ-UHFFFAOYSA-N Diisopropyl ether Chemical compound CC(C)OC(C)C ZAFNJMIOTHYJRJ-UHFFFAOYSA-N 0.000 description 1
- QXNVGIXVLWOKEQ-UHFFFAOYSA-N Disodium Chemical compound [Na][Na] QXNVGIXVLWOKEQ-UHFFFAOYSA-N 0.000 description 1
- 244000028419 Styrax benzoin Species 0.000 description 1
- 235000000126 Styrax benzoin Nutrition 0.000 description 1
- 235000008411 Sumatra benzointree Nutrition 0.000 description 1
- 150000001252 acrylic acid derivatives Chemical class 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 150000005215 alkyl ethers Chemical class 0.000 description 1
- 229920003144 amino alkyl methacrylate copolymer Polymers 0.000 description 1
- PYKYMHQGRFAEBM-UHFFFAOYSA-N anthraquinone Natural products CCC(=O)c1c(O)c2C(=O)C3C(C=CC=C3O)C(=O)c2cc1CC(=O)OC PYKYMHQGRFAEBM-UHFFFAOYSA-N 0.000 description 1
- 150000004056 anthraquinones Chemical class 0.000 description 1
- 229960002130 benzoin Drugs 0.000 description 1
- 229920006317 cationic polymer Polymers 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 238000007872 degassing Methods 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- POLCUAVZOMRGSN-UHFFFAOYSA-N dipropyl ether Chemical class CCCOCCC POLCUAVZOMRGSN-UHFFFAOYSA-N 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 238000010410 dusting Methods 0.000 description 1
- 230000008030 elimination Effects 0.000 description 1
- 238000003379 elimination reaction Methods 0.000 description 1
- 125000001495 ethyl group Chemical group [H]C([H])([H])C([H])([H])* 0.000 description 1
- 230000007717 exclusion Effects 0.000 description 1
- 230000003311 flocculating effect Effects 0.000 description 1
- 239000012634 fragment Substances 0.000 description 1
- 239000008187 granular material Substances 0.000 description 1
- 235000019382 gum benzoic Nutrition 0.000 description 1
- 231100001261 hazardous Toxicity 0.000 description 1
- 125000002768 hydroxyalkyl group Chemical group 0.000 description 1
- 238000010348 incorporation Methods 0.000 description 1
- 239000003999 initiator Substances 0.000 description 1
- 229910052806 inorganic carbonate Inorganic materials 0.000 description 1
- 235000013372 meat Nutrition 0.000 description 1
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 description 1
- 150000002734 metacrylic acid derivatives Chemical class 0.000 description 1
- FQPSGWSUVKBHSU-UHFFFAOYSA-N methacrylamide Chemical compound CC(=C)C(N)=O FQPSGWSUVKBHSU-UHFFFAOYSA-N 0.000 description 1
- 125000005395 methacrylic acid group Chemical class 0.000 description 1
- 125000002496 methyl group Chemical group [H]C([H])([H])* 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 229920000620 organic polymer Polymers 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 239000002685 polymerization catalyst Substances 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 239000013535 sea water Substances 0.000 description 1
- HRZFUMHJMZEROT-UHFFFAOYSA-L sodium disulfite Chemical compound [Na+].[Na+].[O-]S(=O)S([O-])(=O)=O HRZFUMHJMZEROT-UHFFFAOYSA-L 0.000 description 1
- 229940001584 sodium metabisulfite Drugs 0.000 description 1
- 235000010262 sodium metabisulphite Nutrition 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 125000001424 substituent group Chemical group 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 231100000331 toxic Toxicity 0.000 description 1
- 230000002588 toxic effect Effects 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
- 239000003643 water by type Substances 0.000 description 1
- 239000004552 water soluble powder Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F2/00—Processes of polymerisation
- C08F2/46—Polymerisation initiated by wave energy or particle radiation
- C08F2/48—Polymerisation initiated by wave energy or particle radiation by ultraviolet or visible light
Definitions
- the present invention relates to the preparation of water-soluble, high molecular weight organic polymers/copolymers especially adapted as polymeric flocculants for the treatment of waste and other impure waters, and, more especially, to the preparation of high molecular weight, water-soluble acrylic polymers or copolymers essentially devoid of residual monomer or monomers.
- an aqueous solution of acrylic monomer or monomers is continuously deposited onto a support in the form of a thin layer, said solution containing a photopolymerization promoter in an amount of 0.005 to 1% by weight with respect to the total weight of the monomer or monomers, and also containing less than 1 mg oxygen per liter of solution; the thin liquid layer is then subjected to irradiation at wavelengths between 300 nm and 450 nm for 1 to 20 minutes, the average power of such radiation being between 20 and 300 watts/m 2 , the gaseous atmosphere enveloping the thin liquid layer having an oxygen content of less than 5% by volume, and the support being cooled in order to facilitate heat removal.
- the thin layer thus subjected to the onset of photopolymerization is maintained on the cooled support and under an atmosphere free of oxygen and is then exposed to a second radiation stage, at wavelengths between 300 and 450 nm for 1 to 20 minutes, the average power of such radiation being between 300 and 2000 watts/m 2 ; thence, in order to effect removal of the residual monomers present in the resulting, at least partially solidified thin layer, the same is stripped from the support and subjected to yet another stage of irradiation, preferably in a cool air atmosphere, said irradiation being at wavelengths of between 300 and 450 nm for 30 minutes to 3 hours, and with the average power of active radiation being between 20 and 300 watts/m 2 .
- the resultant film is subsequently cut into fragments, dried and ground into powder.
- This process yields polymer having a content of residual monomer or monomers of less than 0.05%.
- it displays the disadvantage of requiring a lengthy period of third-stage irradiation (30 minutes to 3 hours) under conditions differing from those of the earlier irradiation stages.
- Such prior art process is both time consuming, as well as expensive.
- a major object of the present invention is the provision of a novel process for the photopolymerization of acrylic monomer(s) into improved polymeric flocculants, which polymeric flocculants are conspicuously devoid of residual monomer(s), and the photopolymerization itself being free of those aforenoted disadvantages and drawbacks.
- the photopolymerization, per se, consistant with the present invention is facilely carried out in accordance with known techniques, advantageously in the presence of either oxygen or air, such as described, for example, in French Pat. No. 2,327,258 which features the incorporation in the photopolymerization recipe of at least 1 ppm of a water-soluble anthraquinone derivative devoid of substituents in the 1-, 4-, 5- and 8-positions and at least 10 ppm of dissolved chloride ion.
- the invention thus, itself features a process for the preparation of high molecular weight acrylic polymers or copolymers having a very low content in residual monomer(s), and wherein a thin liquid layer of an aqueous solution of an acrylic monomer or acrylic monomers having a pH between approximately 4 and 14, and further comprising a photopolymerization promoter, is continuously deposited on a support and the thin liquid layer exposed to irradiation with radiation having wavelengths between about 300 nanometers and 450 nanometers for such period of time until a thin rubbery layer results, the subject photopolymerization being characterized in that the resultant rubbery layer is first coated on at least one of its two face surfaces with at least one alkali metal sulfite and/or metabisulfite, and that the thus coated thin rubbery layer is next cut into flakes, or otherwise fragmented, and such flakes, etc., are thence dried and ground into powder.
- the powder obtained according to the invention displays a content of residual monomer or monomers of less than 0.05%.
- a mixture of an alkali metal sulfite and/or metabisulfite is utilized for the coating operation, and which itself is in powder form. Even more preferably, the powder used for coating has a grain size of less than 0.1 mm.
- At least one of the two face surfaces of the thin rubbery layer is coated with an amount of sulfite and/or metabisulfite between approximately 0.1% and 3% by weight with respect to the total weight of said rubbery layer. Preferably, an amount between 0.3% and 2% is used. It is preferred to employ either sodium sulfite, Na 2 SO 3 , or sodium metabisulfite, Na 2 S 2 O 5 .
- a flocculant having a very low content in residual monomer or monomers is always obtained, but such flocculant does not always provide a clear solution, or same has a lower molecular weight which adversely affects its flocculating capability.
- Such carbonate does not itself participate or aid in the elimination or exhaustion of the residual monomer(s) but serves to maintain the optimum flocculant activity or capability of the resultant polymer.
- the alkali metal/ammonium carbonate utilized is sodium carbonate.
- the addition of the alkali metal/ammonium carbonate is not necessary to obtain a polymer having an optimized degree of flocculant activity.
- the process according to the invention is especially well suited for the photopolymerization of an aqueous solution of a monomer or monomers deposited on suitable support in a thin layer having a thickness of approximately 2 to 20 mm and containing 0.005 to 1% by weight with respect to the monomer or monomers of a photopolymerization promoter, and containing less than 1 mg dissolved oxygen per liter of solution.
- This layer is subsequently exposed for 5 to 20 minutes to the action of radiation having the aforementioned wavelengths, the average power of such irradiation being 20 to 2000 watts/m 2 and same being progressively applied, with the gaseous atmosphere enveloping the liquid layer having an oxygen content of less than 5% by volume and the support preferably being cooled to dissipate or eliminate the heat generated during polymerization.
- the process of the invention is well adapted for the photopolymerization of acrylic monomers into polymers or copolymers of, e.g., acrylamide, methacrylamide, acrylonitrile, acrylic and methacrylic acids, their salts and esters, aminoalkyl acrylates and methacrylates and quaternized derivatives thereof, the hydroxyalkyl(meth)acrylates, and admixtures thereof. It is especially well adapted for the photopolymerization of acrylamide, because the polyacrylamides are those particular polymers most effected by the aforenoted regulations and standards.
- concentration in the initial aqueous solution may vary.
- concentration will typically range from between 20 and 60% by weight, and preferably between 40 and 50%.
- concentration must be higher; advantageously it is between 40 and 90% by weight, preferably between 50 and 85%.
- concentration is between 40 and 85%.
- the starting solution of the monomer or monomers necessarily contains, prior to its deposition on the support, a photopolymerization initiator that is preferably soluble in the monomer or in at least one of the monomers.
- a photopolymerization initiator that is preferably soluble in the monomer or in at least one of the monomers.
- the photoinitiators that may be used in the process of the invention are of known type. Representative are benzoin and the alkyl ethers thereof, such as, for example, the methyl, ethyl and propyl ethers.
- the solution to be polymerized is prepared with the exclusion of air therefrom, because the operation is to be performed in an oxygen-free atmosphere and in the absence of light from the moment that the photoinitiator is incorporated.
- said solution is deposited on an endless stainless steel belt comprising two lateral flanges (for retaining the solution).
- the gaseous atmosphere or environment over the belt is confined by suitable glass plates and same is purged of oxygen by means of a stream of nitrogen when the operation is to be conducted in the absence of oxygen.
- a bank or plurality of lamps is disposed (for example, low pressure mercury vapor lamps).
- the underside of the metal belt is cooled during the polymerization process via jets of cold water.
- Coating of such resultant rubbery layer with the alkali metal sulfite and/or metabisulfite, and optionally with the carbonate may be effected by any suitable means.
- a simple coating application utilizing brushes is one example.
- the face surfaces of the photopolymerized layer are themselves slightly adhesive, and more or less malleable, such that the powdered mixture is adhered thereto simply by means of friction and pressure.
- the layer coated in this manner is next subjected to a cutting operation into flakes or the like, by means of any suitable apparatus which both cuts and also intimately admixes the inner and outer sections of the layer and thus promotes the effective action of the powdery mixture which had been coated onto the face surfaces of said rubbery layer.
- a shredder of meat grinder type too may be used, wherein a metal Archimedes screw rotates in a cylinder such that the external sections of the thread are closely contiguous the internal surface of the cylinder, but without actually touching same. The screw is thus able to force the rubbery layer against a perforated plate having a large number of holes, which acts as a draw plate for the comminuted product.
- the diameters of such holes are typically several millimeters (1-10 mm) and the number of holes is such that the force necessary for extrusion is not incompatible with the power applied to move the screw.
- the extrusion is aided by blades that are integral with the screw and too are rotating as the extrusion is converted into flakes.
- the plastic flakes recovered at the outlet of the shredder still contain 60 to 40% water, a small amount of sulfite and/or metabisulfite and possibly also the carbonate and trace amounts of residual monomer or monomers.
- the powders of the polymer of copolymer obtained contain less than 0.05% of residual monomer or monomers.
- the subject process may be continuously operated.
- the endless steel belt then is conveyed under lamps of increasing intensity, and the post-polymerization operations are also conducted continuously.
- a solution was prepared from the following ingredients:
- the thin liquid layer was exposed for 15 minutes to irradiation via three ultraviolet lamps of actinic type (Philipps TLADK 30 W 05 type), with the intensity of the lamps, located above the horizontal glass confining plate, progressively increasing from 330 watts/m 2 to 1000 watts/m 2 . After 15 minutes of irradiation, a thin rubbery layer having a thickness of 4.5 to 5 mm was obtained.
- actinic type Philipps TLADK 30 W 05 type
- the thin rubbery layer was brush coated following stripping from the plate on both face surfaces with a powder of neutral sodium sulfite having an average grain size of 0.1 mm.
- a powder of neutral sodium sulfite having an average grain size of 0.1 mm.
- the coated layer was then cut into strips and said strips introduced into a shredder and there shredded.
- the flakes obtained were dried at 75° C. for 45 minutes.
- the granules thus obtained were ground into a powder having a grain size of less than 1 mm.
- the resultant powder contained 0.034% acrylamide and was perfectly white. Same dissolved very rapidly to provide a highly viscous solution having a concentration of 0.5% in the pure water, the Brookfield viscosity thereof being greater than 2500 cps.
- a solution was prepared from the following ingredients:
- Example 1 To this solution, 1.27 ml of a solution of 34 g/l benzoin isopropyl ether in acrylic acid was added. The pH was adjusted to 9.5 by addition of a 10% sodium hydroxide solution. The operation was then continued as set forth in Example 1, with the intensity of the lamps progressively increasing from 660 watts/m 2 to 1000 watts/m 2 .
- the rubbery layer obtained was coated with 0.8% by weight, with respect to the total weight of the rubbery layer, of a mixture containing 50% Na 2 CO 3 and 50% sodium sulfite, with the grain size of said admixture being 0.1 mm. After shredding, drying at 45° C. for approximately 1 hour and grinding, a powder containing less than 0.05% acrylamide was obtained.
- a solution was prepared from the following ingredients:
- a solution was prepared from the following ingredients:
Abstract
The thin rubbery layer resulting from the photopolymerization of a thin layer of an aqueous solution of acrylic monomer(s) is face surface coated with a coating of an alkali metal sulfite and/or metabisulfite, and is then shredded, dried and ground to provide acrylic polymer/copolymer from which virtually all residual monomer has been depleted and which is well suited for use as a polymeric flocculant.
Description
1. Field of the Invention
The present invention relates to the preparation of water-soluble, high molecular weight organic polymers/copolymers especially adapted as polymeric flocculants for the treatment of waste and other impure waters, and, more especially, to the preparation of high molecular weight, water-soluble acrylic polymers or copolymers essentially devoid of residual monomer or monomers.
2. Description of the Prior Art
It is well known to this art that, for reasons of toxicity, it is exceedingly important to utilize for water treatment, e.g., water purification, organic water-soluble polymers or copolymers containing but very slight amounts of residual monomer or monomers. Indeed, different government regulations have set an acceptable upper limit on the content of residual monomer or monomers (particularly in the case of acrylamide polymers or copolymers) at 0.05% by weight, with respect to the weight of the dry polymer.
The preparation of acrylic polymers or copolymers by photopolymerization under ultraviolet irradiation too is well known to the prior art. Compare U.S. Pat. No. 4,178,221 which features the preparation of water-soluble acrylic polymers of high molecular weight containing little or no free monomer. According to this particular process, an aqueous solution of acrylic monomer or monomers is continuously deposited onto a support in the form of a thin layer, said solution containing a photopolymerization promoter in an amount of 0.005 to 1% by weight with respect to the total weight of the monomer or monomers, and also containing less than 1 mg oxygen per liter of solution; the thin liquid layer is then subjected to irradiation at wavelengths between 300 nm and 450 nm for 1 to 20 minutes, the average power of such radiation being between 20 and 300 watts/m2, the gaseous atmosphere enveloping the thin liquid layer having an oxygen content of less than 5% by volume, and the support being cooled in order to facilitate heat removal. Next, the thin layer thus subjected to the onset of photopolymerization is maintained on the cooled support and under an atmosphere free of oxygen and is then exposed to a second radiation stage, at wavelengths between 300 and 450 nm for 1 to 20 minutes, the average power of such radiation being between 300 and 2000 watts/m2 ; thence, in order to effect removal of the residual monomers present in the resulting, at least partially solidified thin layer, the same is stripped from the support and subjected to yet another stage of irradiation, preferably in a cool air atmosphere, said irradiation being at wavelengths of between 300 and 450 nm for 30 minutes to 3 hours, and with the average power of active radiation being between 20 and 300 watts/m2. The resultant film is subsequently cut into fragments, dried and ground into powder. This process yields polymer having a content of residual monomer or monomers of less than 0.05%. However, it displays the disadvantage of requiring a lengthy period of third-stage irradiation (30 minutes to 3 hours) under conditions differing from those of the earlier irradiation stages. Thus, such prior art process is both time consuming, as well as expensive.
It too has been postulated that the aforesaid lengthy period of irradiation of from 30 minutes to 3 hours could be avoided by simply extracting the residual monomer(s) with any suitable solvent, such as dilute methanol. And indeed the ultimate product of photopolymerization may be treated with methanol to dissolve the residual monomers, but this is a lengthy, costly and difficult operation, especially in light of the hazardous and toxic character of methanol.
Other techniques are also known for reducing the residual monomer content of water-soluble polymers, e.g., those featuring the use of the alkali metal sulfites or metabisulfites. Such sulfites or bisulfites are post-polymerization additives, being introduced after completion of the polymerization into aqueous mixtures containing the polymer, the polymer then being dried. If such compounds are present during polymerization, however, they interfere with the polymerization catalyst and upset the process equilibrium. Utilization of such compounds may thus be considered to be confined to already polymerized products. It is also known that it is fundamentally impossible to attain the desired results by interacting the sulfite or bisulfite with a powder of the polymeric flocculant, such as that obtained after drying. In the case wherein a solid, rubbery product is obtained after polymerization, and still containing a high proportion of residual monomer or monomers (0.5% of acrylamide monomer, for example), no means are provided by the prior art for interreaction between the sulfite or bisulfite and the product of photopolymerization.
Hence, it will be seen that a serious need exists in this art for a facile and speedy process for the preparation of water-soluble acrylic polymers or copolymers having a very low residual content of starting material monomer or monomers, and especially for the preparation of such polymers/copolymers well suited as markedly effective polymeric flocculants.
Accordingly, a major object of the present invention is the provision of a novel process for the photopolymerization of acrylic monomer(s) into improved polymeric flocculants, which polymeric flocculants are conspicuously devoid of residual monomer(s), and the photopolymerization itself being free of those aforenoted disadvantages and drawbacks.
Briefly, it has now surprisingly been determined that if an alkali metal sulfite or metabisulfite is interacted with that thin, rubbery layer resulting from the thin layer photopolymerization of acrylic monomer(s), such layer will be essentially completely depleted of its residual monomer(s) content, whereby there is rapidly and quite simply obtained an improved polymeric flocculant which meets all prevailing government toxicity standards.
More particularly, the photopolymerization, per se, consistant with the present invention, is facilely carried out in accordance with known techniques, advantageously in the presence of either oxygen or air, such as described, for example, in French Pat. No. 2,327,258 which features the incorporation in the photopolymerization recipe of at least 1 ppm of a water-soluble anthraquinone derivative devoid of substituents in the 1-, 4-, 5- and 8-positions and at least 10 ppm of dissolved chloride ion.
The invention, thus, itself features a process for the preparation of high molecular weight acrylic polymers or copolymers having a very low content in residual monomer(s), and wherein a thin liquid layer of an aqueous solution of an acrylic monomer or acrylic monomers having a pH between approximately 4 and 14, and further comprising a photopolymerization promoter, is continuously deposited on a support and the thin liquid layer exposed to irradiation with radiation having wavelengths between about 300 nanometers and 450 nanometers for such period of time until a thin rubbery layer results, the subject photopolymerization being characterized in that the resultant rubbery layer is first coated on at least one of its two face surfaces with at least one alkali metal sulfite and/or metabisulfite, and that the thus coated thin rubbery layer is next cut into flakes, or otherwise fragmented, and such flakes, etc., are thence dried and ground into powder.
The powder obtained according to the invention displays a content of residual monomer or monomers of less than 0.05%.
According to a preferred embodiment of the invention, a mixture of an alkali metal sulfite and/or metabisulfite is utilized for the coating operation, and which itself is in powder form. Even more preferably, the powder used for coating has a grain size of less than 0.1 mm.
According to another preferred embodiment of the invention, at least one of the two face surfaces of the thin rubbery layer is coated with an amount of sulfite and/or metabisulfite between approximately 0.1% and 3% by weight with respect to the total weight of said rubbery layer. Preferably, an amount between 0.3% and 2% is used. It is preferred to employ either sodium sulfite, Na2 SO3, or sodium metabisulfite, Na2 S2 O5.
When the pH of the aqueous solution of the starting material monomer or monomers is initially less than 12, a flocculant having a very low content in residual monomer or monomers is always obtained, but such flocculant does not always provide a clear solution, or same has a lower molecular weight which adversely affects its flocculating capability. In such cases, it is advantageous, but not obligatory, to utilize for the coating of the rubbery layer, simultaneously with the alkali metal sulfite and/or metabisulfite, at least one inorganic carbonate selected from the group comprising the alkali metal carbonates and ammonium carbonate. Such carbonate does not itself participate or aid in the elimination or exhaustion of the residual monomer(s) but serves to maintain the optimum flocculant activity or capability of the resultant polymer. In this case, it is preferred to utilize an admixture of the alkali metal/ammonium carbonate and the alkali metal sulfite and/or metabisulfite containing approximately 0 to 60% by weight of the alkali metal/ammonium carbonate and 40% to 100% by weight of the alkali metal sulfite and/or metabisulfite. According to a preferred embodiment of the invention, the alkali metal/ammonium carbonate utilized is sodium carbonate.
When the pH of the aqueous solution of the starting material monomer or monomers is initially higher than 12, the addition of the alkali metal/ammonium carbonate is not necessary to obtain a polymer having an optimized degree of flocculant activity.
The process according to the invention is especially well suited for the photopolymerization of an aqueous solution of a monomer or monomers deposited on suitable support in a thin layer having a thickness of approximately 2 to 20 mm and containing 0.005 to 1% by weight with respect to the monomer or monomers of a photopolymerization promoter, and containing less than 1 mg dissolved oxygen per liter of solution. This layer is subsequently exposed for 5 to 20 minutes to the action of radiation having the aforementioned wavelengths, the average power of such irradiation being 20 to 2000 watts/m2 and same being progressively applied, with the gaseous atmosphere enveloping the liquid layer having an oxygen content of less than 5% by volume and the support preferably being cooled to dissipate or eliminate the heat generated during polymerization.
The process of the invention is well adapted for the photopolymerization of acrylic monomers into polymers or copolymers of, e.g., acrylamide, methacrylamide, acrylonitrile, acrylic and methacrylic acids, their salts and esters, aminoalkyl acrylates and methacrylates and quaternized derivatives thereof, the hydroxyalkyl(meth)acrylates, and admixtures thereof. It is especially well adapted for the photopolymerization of acrylamide, because the polyacrylamides are those particular polymers most effected by the aforenoted regulations and standards.
Depending upon the particular nature of the monomer photopolymerized, its concentration in the initial aqueous solution may vary. Thus, for acrylamide or mixtures thereof with the alkali metal acrylates, such concentration will typically range from between 20 and 60% by weight, and preferably between 40 and 50%. If it is desired to prepare a cationic polymer (a polymer having positive charges along its backbone) comprising a quaternized aminoalkyl methacrylate (chloride), the concentration must be higher; advantageously it is between 40 and 90% by weight, preferably between 50 and 85%. If it is desired to obtain a quaternized aminoalkyl methacrylate and acrylamide copolymer, useful concentrations of these monomers are between 40 and 85%.
The starting solution of the monomer or monomers necessarily contains, prior to its deposition on the support, a photopolymerization initiator that is preferably soluble in the monomer or in at least one of the monomers. The photoinitiators that may be used in the process of the invention are of known type. Representative are benzoin and the alkyl ethers thereof, such as, for example, the methyl, ethyl and propyl ethers.
In a general manner, the process according to the invention may be carried out as follows:
The solution to be polymerized is prepared with the exclusion of air therefrom, because the operation is to be performed in an oxygen-free atmosphere and in the absence of light from the moment that the photoinitiator is incorporated. After optionally degassing the solution with nitrogen to eliminate any oxygen, said solution is deposited on an endless stainless steel belt comprising two lateral flanges (for retaining the solution). The gaseous atmosphere or environment over the belt is confined by suitable glass plates and same is purged of oxygen by means of a stream of nitrogen when the operation is to be conducted in the absence of oxygen. Above the endless metal belt onto which the solution is deposited, a bank or plurality of lamps is disposed (for example, low pressure mercury vapor lamps). The underside of the metal belt is cooled during the polymerization process via jets of cold water.
After 5 to 20 minutes of polymerization, a rubbery layer is obtained, which is then removed or stripped from the steel support.
Coating of such resultant rubbery layer with the alkali metal sulfite and/or metabisulfite, and optionally with the carbonate may be effected by any suitable means. A simple coating application utilizing brushes is one example.
The face surfaces of the photopolymerized layer are themselves slightly adhesive, and more or less malleable, such that the powdered mixture is adhered thereto simply by means of friction and pressure.
The layer coated in this manner is next subjected to a cutting operation into flakes or the like, by means of any suitable apparatus which both cuts and also intimately admixes the inner and outer sections of the layer and thus promotes the effective action of the powdery mixture which had been coated onto the face surfaces of said rubbery layer. A shredder of meat grinder type too may be used, wherein a metal Archimedes screw rotates in a cylinder such that the external sections of the thread are closely contiguous the internal surface of the cylinder, but without actually touching same. The screw is thus able to force the rubbery layer against a perforated plate having a large number of holes, which acts as a draw plate for the comminuted product. The diameters of such holes are typically several millimeters (1-10 mm) and the number of holes is such that the force necessary for extrusion is not incompatible with the power applied to move the screw. The extrusion is aided by blades that are integral with the screw and too are rotating as the extrusion is converted into flakes.
The plastic flakes recovered at the outlet of the shredder still contain 60 to 40% water, a small amount of sulfite and/or metabisulfite and possibly also the carbonate and trace amounts of residual monomer or monomers.
The higher temperature employed during the subsequent drying of the flakes completes the mixing action. After final grinding, the powders of the polymer of copolymer obtained contain less than 0.05% of residual monomer or monomers.
The subject process may be continuously operated. The endless steel belt then is conveyed under lamps of increasing intensity, and the post-polymerization operations are also conducted continuously.
In order to further illustrate the present invention and the advantages thereof, the following specific examples are given, it being understood that same are intended only as illustrative and in nowise limitative.
A solution was prepared from the following ingredients:
[i] Water: 130 g,
[ii] Acrylic acid: 35.1 g,
[iii] NaOH, 50%: 39 g, and
[iv] Sodium gluconate: 1.8 g.
To this solution, 95 g of acrylamide powder were added which dissolved endothermically. While excluding light, 1.25 ml of a solution of 34 g/l benzoin isopropyl ether in acrylic acid were added. The pH was adjusted to 12 with 10% sodium hydroxide. The solution was then degassed with nitrogen to eliminate the oxygen. Said solution was next deposited on a stainless steel belt fitted with bordering flanges, 35 cm long and 18 cm wide, such as to form a layer having a uniform thickness of approximately 4.5 mm. The gaseous atmosphere enveloping the liquid layer, and confined by a glass plate arrangement, had been purged of oxygen prior to the introduction of the liquid mixture by means of a stream of nitrogen.
The thin liquid layer was exposed for 15 minutes to irradiation via three ultraviolet lamps of actinic type (Philipps TLADK 30 W 05 type), with the intensity of the lamps, located above the horizontal glass confining plate, progressively increasing from 330 watts/m2 to 1000 watts/m2. After 15 minutes of irradiation, a thin rubbery layer having a thickness of 4.5 to 5 mm was obtained.
Analysis of the powder obtained after shredding and drying confirmed that it contained 0.3 to 0.5% of residual acrylamide.
A reduction in the amount of the residual acrylamide to 0.034% was carried out utilizing the process of the invention, thus: the thin rubbery layer was brush coated following stripping from the plate on both face surfaces with a powder of neutral sodium sulfite having an average grain size of 0.1 mm. For this purpose, 0.5 to 0.9% by weight of sodium sulfite, with respect to the total weight of the rubbery layer, was employed.
The coated layer was then cut into strips and said strips introduced into a shredder and there shredded. The flakes obtained were dried at 75° C. for 45 minutes. The granules thus obtained were ground into a powder having a grain size of less than 1 mm.
The resultant powder contained 0.034% acrylamide and was perfectly white. Same dissolved very rapidly to provide a highly viscous solution having a concentration of 0.5% in the pure water, the Brookfield viscosity thereof being greater than 2500 cps.
A solution was prepared from the following ingredients:
[i] Water: 157 g,
[ii] Acrylamide: 144 g,
[iii] Isopropanol: 0.14 ml, and
[iv] Sodium gluconate: 1.8 g.
To this solution, 1.27 ml of a solution of 34 g/l benzoin isopropyl ether in acrylic acid was added. The pH was adjusted to 9.5 by addition of a 10% sodium hydroxide solution. The operation was then continued as set forth in Example 1, with the intensity of the lamps progressively increasing from 660 watts/m2 to 1000 watts/m2.
The rubbery layer obtained was coated with 0.8% by weight, with respect to the total weight of the rubbery layer, of a mixture containing 50% Na2 CO3 and 50% sodium sulfite, with the grain size of said admixture being 0.1 mm. After shredding, drying at 45° C. for approximately 1 hour and grinding, a powder containing less than 0.05% acrylamide was obtained.
For purposes of comparison, a thin rubbery layer which had not been treated with the Na2 CO3 /Na2 SO3 admixture evidenced an amount of residual acrylamide monomer in the product ground powder of 0.15%.
The same rubbery layer coated without the Na2 CO3 being present, i.e., coating the rubbery layer only with Na2 SO3, yielded a greyish powder which upon dissolution in water formed slightly opalescent solutions, thus indicating the presence of insolubles. Furthermore, ultimate viscosities in this case were lower; for example, when sodium sulfite alone was used, for a 0.5% by weight solution of polymer in water containing 5% salt from sea water, a viscosity of 100 cps was obtained, whereas 120 cps resulted when the Na2 CO3 -Na2 SO3 admixture was employed.
A solution was prepared from the following ingredients:
[i] Water: 162 g,
[ii] Acrylamide: 118.6 g,
[iii] Sodium gluconate: 3.2 g,
[iv] Isopropanol: 0.4 ml, and
[v] Ethyltrimethylammonium methacrylate chloride: 16.2 g.
To this solution, 1.16 ml of a solution of 34 g/l benzoin isopropyl ether in methanol was added. The pH was adjusted to 8 with 10% ammonia. Photopolymerization was effected as in Example 2. The resulting rubbery layer was coated with 0.7 to 0.9% admixture of 60% Na2 CO3 and 40% Na2 SO3, and was then shredded and dried at 75° C. for 1 hour. After grinding, a completely water-soluble powder containing 0.05% acrylamide was obtained.
For purposes of comparison, the aforesaid procedure was repeated, but without dusting the rubbery layer with the Na2 CO3 /Na2 SO3 admixture, and a powder containing 0.41% acrylamide was obtained.
On the other hand, when only the sodium sulfite was used, without the sodium carbonate, a powder was obtained which dissolved less readily and which comprised an insoluble fraction.
When the Na2 CO3 was replaced by ammonium carbonate, exactly the same results were obtained as with the Na2 CO3 admixture.
A solution was prepared from the following ingredients:
[i] Water: 127.7 g,
[ii] Ethyltrimethylammonium methacrylate chloride: 39.5 g,
[iii] Acrylamide: 129 g, and
[iv] Sodium gluconate: 3.9 g.
To this solution, 1.9 ml of a solution of 34 g/l isopropyl ether in an equal volume of a mixture of methanol and isopropanol were added. The pH was adjusted to 7 with 10% ammonia. Photopolymerization was effected as in Example 2 and the rubbery layer was coated with a mixture of 60% Na2 CO3 and 40% Na2 SO3. After shredding, drying and grinding, a white powder providing a clear aqueous solution and containing 0.05% acrylamide, was obtained.
For purposes of comparison, the procedure outlined above was repeated, but without including the treatment of the rubbery layer with the Na2 CO3 /Na2 SO3 admixture; a powder containing 0.15% residual acrylamide monomer was obtained.
While the invention has been described in terms of various preferred embodiments, the skilled artisan will appreciate that various modifications, substitutions, omissions, and changes may be made without departing from the spirit thereof. Accordingly, it is intended that the scope of the present invention be limited solely by the scope of the following claims.
Claims (17)
1. A process for the removal of residual monomer from the thin, adhesive, rubbery layer resulting from the photopolymerization of a thin layer of an aqueous solution of acrylic monomer selected from the group consisting of acrylamide, acrylic acid and methacrylic acid and the salts and esters thereof, aminoalkylacrylate and aminoalkylmethacrylate and quaternaries thereof, acrylonitrile, hydroxyalkylacrylate and hydroxylalkylmethacrylate, and mixtures thereof, comprising coating at least one face surface of such thin rubbery, adhesive layer with a powder comprising at least one member selected from the group consisting of an alkali metal sulfite and an alkali metal bisulfite, comminuting said coated, thin rubbery, adhesive layer so as to admix inner and outer portions of said layer, extruding said comminuted and admixed layer to form particulates, and drying and grinding the particulates.
2. The process as defined in claim 1, said ground particulates having a content in residual monomer of less than 0.05% by weight.
3. The process as defined by claim 1, said powder having a grain size of less than 0.1 mm.
4. The process as defined by claims 1, said coating comprising from about 0.1% to 3% by weight of the total weight of said thin rubbery layer.
5. The process as defined by claim 4, said coating comprising from about 0.3% to 2% by weight of the total weight of said thin rubbery layer.
6. The process as defined by claim 4, said at least one member being sodium sulfite, sodium bisulfite, or admixtures thereof.
7. The process as defined by claim 4, said coating further comprising a member selected from the group consisting of an alkali metal carbonate and an ammonium carbonate.
8. The process as defined by claim 7, said coating comprising up to 60% by weight of said carbonate.
9. The process as defined by claim 8, said carbonate being sodium carbonate.
10. The process as defined by claim 8, said carbonate being ammonium carbonate.
11. The process as defined by claim 7, said aqueous solution photopolymerized having a pH of less than 12.
12. The process as defined by claim 1, said aqueous solution photopolymerized having a pH of greater than 12.
13. The process as defined by claim 1, said aqueous solution photopolymerized having a thickness of from about 2 to 20 mm.
14. The process as defined by claim 1, said aqueous solution photopolymerized comprising a catalyzing amount of a photoinitiator.
15. The process as defined by claim 1, said monomer being acrylamide.
16. The process as defined by claim 1, both face surfaces of said thin rubbery layer being coated.
17. The process as defined in claim 1, wherein the concentration of said acrylic monomer in said aqueous solution ranges between about 40 to 60 percent by weight.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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FR7908596A FR2453185A1 (en) | 1979-04-05 | 1979-04-05 | PROCESS FOR THE PREPARATION OF WATER-SOLUBLE ACRYLIC POLYMERS OR COPOLYMERS WITH HIGH MOLECULAR WEIGHT AND LOW MONOMER (S) CONTENT |
FR7908596 | 1979-04-05 |
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US (1) | US4306955A (en) |
EP (1) | EP0017555B1 (en) |
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AU (1) | AU534765B2 (en) |
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CA (1) | CA1141329A (en) |
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FR (1) | FR2453185A1 (en) |
HU (1) | HU190662B (en) |
NO (1) | NO155139C (en) |
RO (1) | RO79701A (en) |
Cited By (11)
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US4466931A (en) * | 1982-08-05 | 1984-08-21 | Gelman Sciences Inc. | Method for manufacturing microporous membrane |
US4790919A (en) * | 1984-06-28 | 1988-12-13 | E. I. Du Pont De Nemours And Company | Process for preparation of electrophoresis gel material |
DE3724709A1 (en) * | 1987-07-25 | 1989-02-02 | Stockhausen Chem Fab Gmbh | METHOD FOR PRODUCING POLYMERISATES WITH LOW RESIDUAL MONOMER CONTENT |
US4863647A (en) * | 1984-06-28 | 1989-09-05 | Baylor Jr Charles | Process for preparation of electrophoresis gel material |
US4920202A (en) * | 1987-04-30 | 1990-04-24 | Nippon Shokubai Kagaku Kogyo Co., Ltd. | Method for production of hydrophilic polymer from hydrated gel polymer |
US5126189A (en) * | 1987-04-21 | 1992-06-30 | Gelman Sciences, Inc. | Hydrophobic microporous membrane |
US5229488A (en) * | 1989-09-04 | 1993-07-20 | Nippon Shokubai Kagaku Kogyo Co., Ltd. | Method for manufacture of an absorbent resin |
US5342582A (en) * | 1992-04-10 | 1994-08-30 | Morton International, Inc. | Apparatus for reprocessing special waste |
US6262141B1 (en) | 1999-10-06 | 2001-07-17 | Cytec Technology Corporation | Process for the preparation of polymers having low residual monomer content |
US20050209411A1 (en) * | 2002-05-13 | 2005-09-22 | Basf Aktiengesellschaft | Method for producing low-odor hydrogel-forming polymers |
US20060036043A1 (en) * | 2002-12-09 | 2006-02-16 | Basf Aktiengesellschaft | Method for the production of low-odor hydrogel-forming polymers |
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FR2489336B1 (en) | 1980-09-04 | 1985-09-13 | Rhone Poulenc Spec Chim | PROCESS FOR THE PREPARATION OF WATER-SOLUBLE POLYMERS OR COPOLYMERS WITH HIGH MOLECULAR WEIGHT AND WITH LOW RESIDUAL MONOMER (S) CONTENT FROM OLEFINICALLY UNSATURATED MONOMERS |
FR2495217A1 (en) * | 1980-11-28 | 1982-06-04 | Rhone Poulenc Ind | Enhanced oil recovery using aq. solns. of acrylic! polymers - prepd. by continuous photo-polymerisation |
JPS57177008A (en) * | 1981-04-24 | 1982-10-30 | Nitto Chem Ind Co Ltd | Polymerization of aqueous solution |
CA1226699A (en) * | 1984-01-13 | 1987-09-08 | Akira Yada | Process for preparing sticky polymers |
CA1253833A (en) * | 1984-11-06 | 1989-05-09 | Akira Yada | Process for preparing water-soluble polymer gel particles |
CA1268732A (en) * | 1984-12-27 | 1990-05-08 | Akira Yada | Radiation-polymerizing water-soluble cast vinyl monomer layer and forming particles |
JPS62235305A (en) * | 1986-04-04 | 1987-10-15 | Dai Ichi Kogyo Seiyaku Co Ltd | Production of high-molecular-weight acrylic polymer |
JPS63260907A (en) * | 1987-04-17 | 1988-10-27 | Mitsubishi Petrochem Co Ltd | Manufacture of highly water-absorptive polymer |
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- 1980-03-24 EP EP80400391A patent/EP0017555B1/en not_active Expired
- 1980-03-24 AT AT80400391T patent/ATE2624T1/en not_active IP Right Cessation
- 1980-03-24 DE DE8080400391T patent/DE3062106D1/en not_active Expired
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- 1980-04-03 HU HU80811A patent/HU190662B/en unknown
- 1980-04-03 FI FI801089A patent/FI67714C/en not_active IP Right Cessation
- 1980-04-03 CA CA000349261A patent/CA1141329A/en not_active Expired
- 1980-04-04 RO RO80100721A patent/RO79701A/en unknown
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Cited By (13)
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US4466931A (en) * | 1982-08-05 | 1984-08-21 | Gelman Sciences Inc. | Method for manufacturing microporous membrane |
US4790919A (en) * | 1984-06-28 | 1988-12-13 | E. I. Du Pont De Nemours And Company | Process for preparation of electrophoresis gel material |
US4863647A (en) * | 1984-06-28 | 1989-09-05 | Baylor Jr Charles | Process for preparation of electrophoresis gel material |
US5126189A (en) * | 1987-04-21 | 1992-06-30 | Gelman Sciences, Inc. | Hydrophobic microporous membrane |
US4920202A (en) * | 1987-04-30 | 1990-04-24 | Nippon Shokubai Kagaku Kogyo Co., Ltd. | Method for production of hydrophilic polymer from hydrated gel polymer |
DE3724709A1 (en) * | 1987-07-25 | 1989-02-02 | Stockhausen Chem Fab Gmbh | METHOD FOR PRODUCING POLYMERISATES WITH LOW RESIDUAL MONOMER CONTENT |
US5229488A (en) * | 1989-09-04 | 1993-07-20 | Nippon Shokubai Kagaku Kogyo Co., Ltd. | Method for manufacture of an absorbent resin |
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US6262141B1 (en) | 1999-10-06 | 2001-07-17 | Cytec Technology Corporation | Process for the preparation of polymers having low residual monomer content |
US20050209411A1 (en) * | 2002-05-13 | 2005-09-22 | Basf Aktiengesellschaft | Method for producing low-odor hydrogel-forming polymers |
US7307132B2 (en) | 2002-05-13 | 2007-12-11 | Basf Aktiengesellschaft | Method for producing low-odor hydrogel-forming polymers |
US20060036043A1 (en) * | 2002-12-09 | 2006-02-16 | Basf Aktiengesellschaft | Method for the production of low-odor hydrogel-forming polymers |
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AU534765B2 (en) | 1984-02-16 |
ATE2624T1 (en) | 1983-03-15 |
JPS6123926B2 (en) | 1986-06-09 |
FI801089A (en) | 1980-10-06 |
JPS55135110A (en) | 1980-10-21 |
FR2453185B1 (en) | 1982-12-17 |
EP0017555A1 (en) | 1980-10-15 |
ES8101083A1 (en) | 1980-12-01 |
ES490221A0 (en) | 1980-12-01 |
NO155139C (en) | 1987-02-18 |
DE3062106D1 (en) | 1983-03-31 |
DK149348C (en) | 1986-10-20 |
EP0017555B1 (en) | 1983-02-23 |
BR8002098A (en) | 1980-11-25 |
CA1141329A (en) | 1983-02-15 |
AU5701880A (en) | 1980-10-09 |
FR2453185A1 (en) | 1980-10-31 |
DK149348B (en) | 1986-05-12 |
FI67714C (en) | 1985-05-10 |
RO79701A (en) | 1982-09-09 |
HU190662B (en) | 1980-10-28 |
NO155139B (en) | 1986-11-10 |
NO800951L (en) | 1980-10-06 |
FI67714B (en) | 1985-01-31 |
DK144880A (en) | 1980-10-06 |
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